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    SubjectRe: [PATCH 5/5] workqueue: retry on NUMA_NO_NODE when create_worker() fails
    On Fri, Dec 12, 2014 at 11:05 AM, KOSAKI Motohiro
    <kosaki.motohiro@gmail.com> wrote:
    > On Fri, Dec 12, 2014 at 5:19 AM, Lai Jiangshan <laijs@cn.fujitsu.com> wrote:
    >> A pwq bound to a specified node might be last long or even forever after
    >> the node was offline. Especially when this pwq has some back-to-back work
    >> items which requeue themselves and cause the pwq can't quit.
    >>
    >> This kinds of pwqs will cause their own pools busy and maybe create workers.
    >> This pools will fail on create_worker() since the node is offline.
    >>
    >> This case is extremely rare, but it is possible. And we hope create_worker()
    >> to be fault-tolerant in this case and other different cases when the node
    >> is lack of memory, for example, create_worker() can try to allocate memory
    >> from the whole system rather than only the target node, the most important
    >> thing is making some progress.
    >>
    >> So the solution is that, when the create_worker() fails on a specified node,
    >> it will retry with NUMA_NO_NODE for further allocation.
    >
    > The code looks correct. But I don't think this issue depend on node offlining.
    > The allocation may also fail if node has no memory.

    Oh, sorry. my comment is no correct. Please forget.


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